Hi,
I will tell a story happened with me and not sure how much is relevant to your case.
I spent a lot of time optimizing my SecureBlackBox v15, the result was astonishing in performance, i did many big rewriting in it and many small tweaks, because well it is expired and working just perfect and secure, so the optimize process went for over a year every now and then, the whole time i was using it in production and not special happens, but after about six month form the last any edit in the library, my Delphi 2010 and Seattle start to refuse to compile my projects which were complied on almost daily bases first 2010 then after days the Seattle, while XE 8 still working fine with the projects that have SBB, it took me hours to find that it was SSB, and it took me days to retract every optimize i did to find the culprit.
In the end it was an "inline" procedure, in SBB i added the inline directive for few functions, and the culprit was FreeAndNil in SBB, it was added by SBB for compatibility reason, for them it is easier for cross languages, in Delphi with inline and in specific constellation it cause the compiler to crash or the whole
IDE to disappear, the strange thing is, when there was a
AV message it was pointing to the
dpr, as i said it was compiling and linking without any problem for months, and then in few days a part two
IDE start to crash and generate unreadable error and failure messages.
So and after sorry for the long story, i would check your libraries for functions and procedures that have same name in system.pas also any intrinsic, and it is important to check if you are overriding any of them too, also try to disable any inline, and see if that helps.
And good luck !